1. Field of the Invention
The invention relates to an illumination device and a display device including the same.
2. Description of the Related Art
In recent years, an illumination device using a light-emitting diode (hereinafter, “LED”) as a light source is utilized in various fields. For example, in projective-type display devices, there exist a device including an illumination device having three types of LEDs as a light source, which generate light of wavelengths corresponding respective color components of red, green and blue which are three primary colors of light. The display device of this type adds lights generated by three types of LEDs to obtain white light. At that time, the color balance of white light obtained by combining three colors (hereinafter, “white balance”) chiefly depends on the relative relationship of light intensity of respective colors. Usually, the white balance is adjusted at the time of factory shipping or the like, however, in actual use after that, there is a case that light-emitting characteristics of the LEDs vary due to temperature change or secular change and the white balance is lost.
For example, in the following JP-A-2004-184852 (Patent Document 1), a technique in which the amount of light from LEDs as light sources is detected by optical sensors (photosensors) to adjust the white balance in accordance with the detected amount of light, or a technique in which a wavelength detection function that detects wavelength information of LED is given to the optical sensors are described. In JP-A-2007-87816 (Patent Document 2), there is disclosed a technique in which a junction temperature of the LED is measured by a temperature sensor as a peripheral temperature to adjust setting items (values concerning power feeding to the LED) in accordance with data of the setting items which is previously stored based on the measured peripheral temperature.